Two-piece firearm bolt



Allg. 12, 1952 dw, A, SCHAlCH 2,606,382

TWO-PIECE FIREARM BOLT Filed Nov. 29, 1948 Swan/HTM Wilbur A B11-ui :.11

Patented Aug. 12, 1952 UNITEDL STATES PATENT OFFICE Y Y l v 2,606,382

v Two-Pinon FIREARM BoL'r Wilbur Schaich, Franklin, Mich. Application November 29, 194s, serial Nc. 62,503

(Granted under the act of March 3, 1883, as I 2 Claims.

amended April30, 1928; 370 0. G. v7,57)

The invention described herein may be manufactured and used by or for the Government for governmental purposes without the payment o any royalty thereon.

This invention relates to an improved firearm construction, and particularly 'to an improved` bolt construction for an automatic rearm incorporating a separable locking member associated with the bolt.

Conventional firearms of the reciprocating bolt type generally accomplish the locking of the bolt -to the receiver in battery position by means of a bolt reciprocating in a receiver would lie in a i tubular receiver having a cylindrical bore in which a generally cylindrical bolt member is mounted for rotative and axial movement. Such economical structure has heretofore been impossible to utilize in any firearm requiring locking lugs cooperating between the bolt and receiver solely because it is not possible to insert a cylindrical bolt with radially projecting lugs into a tubular bore of substantially the same size as the bolt without cutting an opening in the receiver wall having a width of at least the diameter of the receiver bore and a length approximately equal to the length of the bolt.

When it is also considered that in most nrearms the remaining half of the receiver wall must provide va cartridge feeding or magazine opening, it is apparent thatV the remaining portion of the receiver wall must be so thick to pron vide the necessary strength requirement that the use of a tubular blank to form the receiver would be more costly than the commonly utilized forging and machining operation.

Accordingly, it is an object of this invention to provide an improved bolt construction for a firearm which will permit the receiver to be economically manufactured from a tubular blank, the bolt to be fabricated from a cylindrical blank, and a separable locking member cooperating with the bolt in such manner as to permit the assembly of the bolt into the tubular receiver by axial movement through the open end of such receiver.

. 2 Y The specific nature of the invention, as well as other objects andadvantages thereof will clearly appear'from the following description of a preferred .embodiment shown in the accompanying drawings in which: f

Fig. 1 is a fragmentary perspective view of a firearm receiver showing a bolt embodying this invention assembled to such` receiver;

Fig. 2 is a side elevational view of the locking member; y f l Fig. 3 isl aside elevational view of theA bolt showing themanner of securing the ring pin within the bolt and preventing rotation of the locking member, such locking member being shown in section.' Y Y v.-

Fig. 4 is afragmentaryperspective View of vthe receiver, particularly showingthe locking .surfaces therein. Y In Fig. 1 there is shown in assembled relation a firearm receiver I5 and a bolt IB-embodying this invention. Bolt I6 and receiver I5 are preferably of cylindrical construction as shown. An axially disposed hole 30 of suitable configuration is providedin boltV I6 to accept a ringpin 3l. The right end of such hole is counterbored as shown at 33 :to accommodate a head 32'integrally formed onf'pin 3|Y and a firing pin retracting spring 34 surrounding such pinV and abutting the head portion thereof. A substantially U-shaped notch 35 of somewhat greater width than that of locking member I 8 .is provided near the forward end of pin 3I for a purpose to presently appear.` -A transverse hole I1 Another object of this invention is to provide is provided at the front end of bolt I6 through which is inserted a rod-.like locking member I8. Locking member I3 is provided to securely lock bolt I6 to receiver I5 as will beV later described. Each end of lockingmevmber i8 is substantially square as shown at I9 and 2D. An integral lug `2I projecting beyond the `squared-end 20 of locking member I8 is provided to engage afcam slot or recess 31 vof an operating rodl 22 for locking and unlocking-of bolt I 6v as will be later explained.

Receiver I5 is provided with oppositely disposed longitudinal ways 23 and 24 which terminate near the forward end of receiver I5 in substantially vertical notches 25 and 25'. Locking surfaces 26 and 26' are provided on the rearward sides of notches 25 and 25', respectively, and each of such surfaces is preferably formed on a suitable helix. One corresponding side of each of the squared ends I9 and 20 of locking member I8 is likewise formed on a similar helix in order that such surface will cooperate flattened for a substantial distance as shown at 36 to lock firing pin 3| within bolt I6 in a manner as will now be described.

Firing pin 3| is assembled withinM hole 3Il'in bolt I6 and such bolt in turn is inserted in re'-A ceiver I5. Bolt I6 is thenmoved forwardly until transverse hole II is aligned with opposed notches 25 and 25'. Locking member I8 -is then readily assembled to bolt IB. Firing pin 3l is of 'operating' rod riz "wur @noot rotao' uiookrngis accentuant-ino; l

e, aigsogM-i, part or misinfaesrniuea here. tis obvious -provddasimpi ooit oostfiotjiori wherein tno rocking 'lues' are kmafie separable from 'theboit member tirobv istinto, lng 'fabrication for me ooitasweu astri@ locking-inenten f fronts: Y 'Y ji. in a rarm-ofcy1inuno1 receiver having a 'tubular soit receiving "bore otono end of oeive, aoylinqricai'toitinsertable insaioi er boreonly 'through said' operi end, 'said m "jsiidaioiy and rotatably movable Vin said toro, saniy 'boit 'having a non-axial' `'or'tmsvorso opening', saia'reoeivofnaving a pair of diametrioa'iiy' opposed 1ongitudmai` Asimi-like openings throng fth'owau thereof toiminogtmgfinl vertical notch portion'o'fgreatef widjtnthan cslo't-i le openings"tlierelcy` rig'a lockingshouldei iin d operi sfad' a iookingnomtef .in-

having a body portion snugly engageable in said bolt opening and an integral locking portion projecting from each end of said body portion into said opposed receiver slot-like openings, each of said locking portions having a locking surface constructed and arranged to cooperate with each o'f said locking shoulders by limited rotation of said bolt within said receiver.

2. In a firearm, the combination of a cylindrical receiver having a bolt receiving bore at one-end of the receiver, a cylindrical bolt insertable in said receiver bore only through said open end, said bolt being slidably and rotatably movable in said bore, said bolt having a non-axial transverse opening, said receiver having a pair of diametrically opposed longitudinal slot-like openings 'through the -Wall thereof terminating in a vertical notch portion of greater Width than said slot-like openings thereby forming a locking shoulder in `each of said openings, a locking mem- .ber insertablethr'ough said Vertical notch portions, said member having a body portionsnugly engageable in said bolt opening and an integral locking portion projecting from each end-of said body Lpo'rti'on into saidopposed receiver slot-like openings, one of said locking'portions terminating in-afca'm 'portion arranged to .protrude beyond said receiver, and a bolt operating member axially recipocably mounted alongthe exterior of said receiver, said bolt operating member having a cam recess disposed adjacent said receiver opening, each of said locking yportions having a locking surface constructed and arranged to "cooperate with said locking shoulder by limited rotation of said bolt within said vreceiver when said cam recess of 'said bolt operating member engagesis'aid caml portion of said locking member.

WILBUR A.SCHA1CH.

RFRECES CITED The 'following' references areV of record inthe -ille of this patent:

VliNITIiD v'Sr-A111513' PA'IEN'TS Number Name Date 1,069,496 Stahl May l5, 1928 2,073,128 `Wadsworth Mar. 9, 1937 2,085,812 Loomis July 6, 1937 2,101,862 MacGregor Dec. 11, 1937 2,224,928 Reising 1 1 Dec. 17, 1940 2,296,242 Brewer f Sept. 22, 1942 2,308,283 Humest'on Jan. 12, 1943 2,336,146 Williams Y Y Dec. 7, 1943 2,338,682 -Bohan Jan. 4, 1944 2,356,595 Koucky Aug. 22, 1944 2,370,233 Crockett Feb. 27, 1945 2,401,616 Clarke June 4, 1946 2,425,684 Patchett Aug. 1.2, 1947 FOREIGN PATENTS Number Country Date 61,257 Denmark Aug. 23, 1943 227,818 Switzerland Oct. 1, 1943 

